Written by Kimiko Dunbar
Spoon Feed
In febrile infants aged 22–90 days, a positive urine culture in the setting of a negative urinalysis occurred in 7.4% of infants, primarily in males.
Is the AAP always right?
In 2021, updated AAP guidelines recommended against a urine culture (UC) in febrile infants 6–60 days if urinalysis (UA) is negative. These recommendations were made on the assumption that the majority of positive UC with a negative UA represented asymptomatic bacteriuria. The objective of this study was to evaluate the appropriateness of these recommendations. This multicenter retrospective study evaluated 2,391 well-appearing febrile infants aged 22–90 days with negative UA to assess the utility of UCs. A negative UA was considered one without the presence of leukocyte esterase or nitrite. Positive UCs in the setting of a negative UA occurred in 7.4%, primarily in males (13.5% vs. 0.6% in females; OR 9.0, 95%CI 4.7–16.9). ANC was a weak predictor (OR 1.0001). Unfortunately, male infants in this study had an unknown circumcision status, making it difficult to understand the impact of circumcision on positive UC rate. Authors presume a high possibility that the majority of male infants in the study were uncircumcised based on the study’s location. This study is otherwise limited by its retrospective design.
How does this change my practice?
While the hospital where I practice has certainly adopted the updated 2021 AAP guidelines, I rarely see a “septic work-up” performed without a urine culture. This could be reflective of clinician ordering patterns; I usually order the UA and culture at the same time out of a (likely irrational) fear that the baby will have to be cathed again if the culture isn’t collected at the same time as the UA. I’m pretty convinced we might not need a culture if the UA is negative, especially in female infants. I’ll be more thoughtful about looking at a UA before ordering a culture, or at least considering the clinical relevance of growth on culture in the setting of a normal UA.
Source
Urine culture findings in well-appearing febrile infants aged 22-90 days with negative urinalysis. Arch Dis Child. 2025 Jun 6:archdischild-2025-328637. doi: 10.1136/archdischild-2025-328637. Epub ahead of print. PMID: 40480680
